Access control systems of various kinds are known in the art. Some access control systems control the automated operation of a movable barrier (such as but not limited to a single piece or segmented garage door or doors of other sorts, a pivoting or sliding gate, arm guards, rolling shutters, and the like) and some control some other aspect of an entry control mechanism (such as but not limited to a remote lock control system and the like). In many cases, the access control system includes an operator (such as a movable barrier operator) that interacts in useful ways with one or more remote user interfaces. For example, the remote user interface can provide a mechanism to permit a user to enter an operating or identifying code via a keypad or by presenting a card having such information encoded thereon.
In some deployments, such a remote user interface may be located a considerable distance from the access control system itself. For example, the remote user interface may be disposed at an entry gate that is many hundreds of feet from a garage or other facility that houses the operator for the access control system. Therefore, such remote user interfaces are often coupled to the access control system by an RS-485 compatible wireline linkage. Those skilled in the art will recognize that the conductor configuration and voltage levels that characterize the RS-485 standard are well suited to the reliable conveyance of relatively long distance control signaling of this type. As a result, such an approach often serves these purposes well.
There are instances, however, when a wireline linkage between an access control system and a remote user interface is difficult to provide. Local elements (such as walls, driveways, bodies of water, and the like) may present physical obstacles to a concealed deployment of the RS-485 wireline link while an exposed deployment may be objectionable on security and/or aesthetic grounds.
Notwithstanding such difficulties, wireless solutions have not been readily adapted as a substitute in many such settings. This is due, at least in part, to the nature of the control signaling itself in many such systems. For example, many such systems convey nine bit messages as between such elements as an access control system platform and a remote user interface. RS-485 readily supports such a message. Unfortunately, many off-the-shelf wireless solutions are not so amenable. In many cases this legacy message format protocol presents a significant point of incompatibility and discourages use of a wireless solution.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.